Coffee powder metering device for coffee vending machines

ABSTRACT

The present invention relates to a coffee powder metering device for coffee vending machines which, besides ensuring that all the coffee powder is metered out with no residue left behind, is also easy to manufacture. 
     The metering device comprises in a structure: a tubular main part, an end wall for closing off one end of the the tubular main part and a thrust wall in the tubular main part opposite the end wall. The tubular main part, end wall and thrust wall thus form a compartment for receiving a given quantity of coffee powder, through an inlet in one of the sides, and forcing it out through the end by utilizing the thrust wall. On the wall facing the compartment, the thrust wall is fitted with at least one movable lip held firmly by way of an elastic device against the tubular main part so as to scrape it clean.

BACKGROUND OF THE INVENTION

The present invention relates to a coffee powder metering device forcoffee vending machines comprising in a structure: a tubular main part,formed by two opposite side panels and two walls, perpendicular to theside panels; an end wall for closing off one end of the tubular mainpart, opened by power means; and a thrust wall inside the tubular mainpart, opposite the end wall and set at an adjustable distance from theend of the tubular main part towards which it is moved by control means.The tubular main part, end wall and thrust wall form a compartment forreceiving a given quantity of coffee power, through an inlet in one ofthe sides, and forcing it out through the end by means of the thrustwall.

Although they offer a number of advantages from certain points of view,known metering devices currently being used all have the followingdrawback in common.

It is practically impossible to ensure that the thrust wall, whichforces the coffee powder out as it slides down the tubular main part,mates perfectly all the way round with the tubular main part, the resultis that, however small, at least part of the edge of the thrust walldoes not contact the tubular main part.

Because of this gap, the thrust wall does not force out all the coffeepowder in the compartment and a small amount, corresponding to the sizeof the gap, is left, on account of its oily nature, on the wall of thetubular main part.

The aim of the present invention is to provide a metering devicedesigned structurally and functionally to overcome the defect of knownsystems.

SUMMARY OF THE INVENTION

The metering device of the present invention specified herein ischaracterised by the fact that, on the wall facing the compartment, thethrust wall is fitted with at least one movable lip held firmly byelastic means against the tubular main part so as to scrape it clean.

Furthermore, the thrust wall is provided with two lips facing thecompartment and hinged together to form a V, each held firmly by elasticmeans against the respective wall of the tubular main part so as toscrape it clean.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the attacheddiagrams, provided by way of a non-limiting example, in which:

FIG. 1 shows a part section in perspective of a metering device,according to the present invention, during the first operating stage;

FIG. 2 shows the FIG. 1 metering device during the second operatingstage.

DESCRIPTION OF A PREFERRED EMBODIMENT

Number 1 in the attached diagrams indicates an overall coffee powdermetering device for coffee vending machines which is of the ordinarytype and therefore not shown. The metering device 1 comprises on thestructure 2: a tubular main part 3, an end wall 4 for closing off oneend 3a of the tubular main part 3, opened by power means describedlater; a thrust wall 5 inside the tubular main part 3, an opposite endwall 4 and set at an adjustable distance from end 3a of the tubular mainpart 3 towards which it is moved by control means described later.Structure 2 consists of two parallel plates, 6 and 7, connected to eachother by pins all marked by number 8. The tubular main part 3 is formedby two side panels, 9 and 10, which, in the example shown, consist oftwo portions of plates 6 and 7 and two walls, 11 and 12, perpendicularto the said side panels 9 and 10.

Tubular main part 3, end wall 4 and thrust wall 5 form a compartment,13, for receiving a given quantity of coffee powder through inlet 14 inside panel 9 and for forcing it out through the end 3a by means ofthrust wall 5, according to the set supply cycle. On the side panel 10,the tubular main part 3 is fitted with a known sensitive-membraneelectric sensor, 15, positioned more or less facing inlet 14. End wall 4rests on and swivels round pin 16, perpendicular to plates 6 and 7, andis fitted with a torsion spring, 17, which exerts constant pressure onthe wall to keep it closed, and power means 18 is provided for openingit.

The power means 18 includes an electromagnet, 19, whose stator, 20, isfitted integral with structure 2 and whose keeper, 21, is tied to endwall 4 on projection 4a with a jerk spring, 22, inbetween. Thrust wall 5is fitted to one end, 23a, of a moving arm, 23, which is hinged at theother end, 23b, to pin 16. Thrust wall 5 is kept well away from end 3aof tubular main part 3 by means consisting of spring 24, one end ofwhich, 24a, is fitted to pin 25 in structure 2 while the other end, 24b,is fitted to arm 23. Spring 24 keeps arm 23 against adjustable stop 26consisting of an ordinary pin, 27, assembled eccentrically on pin 28 onplate 6 so that it can be moved angularly for making the adjustment. Thecontrol means, 29, for moving wall 5 against the effect of the saidelastic means, consist of projection 30 on wall 4 and screw 31, also onwall 4, which engages with arm 23 for turning it round when the end wallopens.

Adjustment screw 31 is set so as to engage arm 23 after the end wall hasturned by a preset amount.

On metering device 1, according to the invention, thrust wall 5 isfitted with two lips, 32 and 33, facing the compartment and hinged toeach other so as to form a V round pin 34 on end 23a of arm 23, eachheld firmly, by elastic means, consisting of spring 35, against eitherof walls 11 and 12 of the tubular main part 3 so as to scrape it clean.

The operation of the metering device according to the invention will nowbe described with reference to the initial condition shown in FIG. 1. Inthis condition, end wall 4 is closed over end 3a of tubular main part 3while thrust wall 5 is at a preset distance from end 3a. By adjustingstop 26, this distance can be adjusted until the volume of compartment13 corresponds to the required amount of coffee powder.

This is poured into compartment 13 through inlet 14 from an ordinarycoffee grinder, for example, not shown in the diagram.

When the compartment is full of coffee, sensor 15 sends out a signalwhich cuts off supply of coffee to the compartment. Coffee is suppliedfrom the compartment by energizing electromagnet 19 which directlycontrols angular displacement of end wall 4 which switches from closedto open. During the initial rotation stage, screw 31 moves forward toengage arm 23. For the remainder of rotation, the end wall is alsoangled by screw 31 so that end wall 5 moves towards end 3a of tubularmain part 3 thus expelling the coffee powder from compartment 13. Lips32 and 33 on wall 5 slide firmly along walls 11 and 12 so as to scrapethem clean.

The main advantage of the metering device according to the presentinvention is that all of the coffee powder is metered out withoutleaving any on the wall of the tubular main part. A further advantage ofthe metering device according to the present invention is that the wallsof the tubular main part need not necessarily be exactly parallel to thethrust wall or even to each other, a feature which provides for easymanufacture.

I claim:
 1. Coffee powder metering device for coffee vending machinescomprising in a structure:a tubular main part, formed by two oppositeside panels and two walls, perpendicular to said side panels; an endwall for closing off one end of the tubular main part, opened by powermeans; a thrust wall inside said tubular main part, opposite the endwall and set at an adjustable distance from said end of the tubular mainpart, said thrust wall is moved by control means; said tubular mainpart, end wall and thrust wall form a compartment for receiving a givenquantity of coffee powder, through an inlet in one of the side panels,and forcing it out through said end by means of the thrust wall, whereinon the two walls facing the compartment, the thrust wall is fitted withtwo lips facing the compartment, hinged to each other so as to form a Vand each held firmly, by elastic means, against the respective walls ofthe two walls of the tubular main part so as to scrape it clean. 2.Metering device according to claim 1, wherein the end wall rests on andswivels round a pin and is fitted with a torsion spring, which exertsconstant pressure on the end wall to keep it closed, and is moved by thesaid power means in opposition to the action of the said torsion spring.3. Metering device according to claim 2, wherein the thrust wall isfitted to one end of an arm which is fitted at the other end to the saidpin and held firmly against an adjustable stop well away from the end ofthe tubular main part by elastic means and moved by the said controlmeans in opposition to the action of the said elastic means.
 4. Ametering device according to claim 3, wherein said arm is a curved armrotatably mounted to said pin.
 5. A metering device according to claim3, wherein said end wall includes a projection and said control meansincludes a screw adjustably mounted in said projection, said screwengages said arm to adjust the distance of the arm from the end of thetubular main part and for moving said arm and said thrust wall aboutsaid pin.
 6. A metering device according to claim 1, wherein said powermeans includes an electromagnet having a stator affixed to saidstructure and a keeper secured to said end wall.
 7. A metering deviceaccording to claim 1, wherein said two walls are curved andsubstantially parallel with respect to each other.